.nav
  width:100%;
  height: 50px;
  position: absolute;
  left: 0px;
  top: 0px;
  background-color: #000;
  color: #fff;
.nav .logo
  width: 100px;
  height: 100%;
  padding-left:20px;
  padding-right: 20px;
  line-height: 50px;
  font-size: 20px;
  text-aligin: center;